A fixing device included in a printer or a copier is known. Such fixing device may include an endless belt, a pressing member, a nip member, a stay, and a heater. The pressing member has a width extending in a widthwise direction of the endless belt and is located outside of a loop of the endless belt so as to contact a peripheral surface of the endless belt. The nip member extends in the widthwise direction of the endless belt and is located inside of the loop of the endless belt such that the endless belt is sandwiched between the nip member and the pressing member. The stay is disposed further inside of the loop of the endless belt than the nip member and is configured to restrict that the nip member moves away from the endless belt. These structures of the fixing device allow a sheet to be heated by the heater while conveyed between the endless belt and the pressing member.
While the stay supports both ends of the nip member in the widthwise direction, a pressure by the pressing member may cause a middle portion of the nip member in the widthwise direction to bend so as to be away from the pressing member. A certain fixing device includes a configuration to offset the middle portion of the nip member toward the pressing member.